Roller pressure bar for veneer lathes



July 31, 1951 W. J. MILLER ET AL ROLLER PRESSURE BAR FOR VENEER LATHES Filed Oct. 22, 1945 IAN/[IV TORS MY/Avm J /W///6/' 192/2750 67 dTobnson Patented July 31, 1951 ROLLER PRESSURE BAR FOR VENEER LATHES William J. Miller and Alfred :GFJ ohnson, Seattle, Wash., assignorsto -Elliott;Bay. Mill 00., Seattle, 'Wash.,'a corporation of Washington;

Application October 22, 1945, Serial No. 623,706

.5 Claims. 1

This invention relates to a roller pressure bar for a veneer lathe and the present invention is in the nature of an improvement on roller pressure bars of the type disclosed in the two patents to George H. Osgood No. 1, 4, issued May 12, 1931, and No. 1,845,515, issued February 16, 1932.

An object of this invention is to provide a roller pressure bar in which the pressure roller that engages the log rests against and is supported on and is frictionally driven by a power operated backing roller that is provided within the pressure bar assembly.

Another object is to provide a roller pressure bar having a frictionally driven pressure roller that contacts the log and that is capable of slippage relative to its driving means to permit the pressure roller to move at the same peripheral speed as the log thereby minimizing the danger of this pressure roller pulling and rupturing the wood as the veneer comes off of the log and in this way conserving wood, increasing the yield of good wood from the logs and making possible the production of better plywood.

Another object is to provide a roller pressure bar in which the pressure roller that contacts the 'log is driven from another roller that carries the driving means and is spaced further from the lathe spindles than the pressure roller thereby making it possible to peel off more of the log or to reduce the log to a core of smaller diamv.eter, before the roll driving means contacts the lathe spindles than would be possible if the driving means were carried directly by the pressure roll. Thismakes it possible to obtain more usable veneer from each block or log thus conserving wood.

Another object is to provide a roller pressure bar for a veneer lathe wherein parts that have sliding contact with each other are made of metals that require a minimum of lubrication thus making it possible to efficiently lubricate these parts with oil without danger of staining or damaging the veneer and in this way eliminating the need for the use of steam or water on these parts, which is objectionable because it adds .moisture to the veneer and because it tends to solidify the soft pitch in fir wood.

.Another object is to provide a roller pressure bar in which all of the parts are quickly and;

.easily accessible for the purpose of servicing,

such as adjustment replacement or repair.

.Another object is to provide a roller pressure bar in which the pressure roller that contacts the logis carried on supporting'means that is notched ment of said plate H.

bark and wood, that might otherwise foul the roller, may discharge and to provide this pressure roller with end thrust bearing means that allows some endwise drifting or augering of said roller back and forth so as to further assist in disposing of dirt and small particles of bark and wood.

Other objects of the invention will be apparent from the following description taken in connection with the accompanying drawings.

In the drawings Figure l is a view in cross section of roller pressure bar means constructed in accordance with this invention showing a fragment of a log and fragments of a lathe with which this pressure bar is connected.

Fig. 2 is a fragmentary view partly in front elevation and partly in section, on a smaller scale than Fig. 1, showing pressure bar means constructed in accordance with this invention.

Fig. 3 is a fragmentary plan view of pressure bar means constructed in accordance with this invention showing fragments of a log and lathe spindle and showing roller driving means connected with a backing roller.

Like reference numerals designate like parts throughout the several views.

In the drawings 5 designates a fragment of the pressure cap of a veneer lathe. This cap 5 is provided, at its front edge and adjacent the position of a log 6 from which veneer is to be peeled, with an L-shaped notch 1 within which our pressure bar assembly is mounted.

This pressure bar assembly comprises a main supporting bar 8 adapted to rest in the L-shaped notch l and rigidly secured to the cap member 6 as by cap screws 9. The top side of the bar 8 is notched in stair step fashion, from its front edge rearwardly, to provide one shelf I0 on which a roller supporting plate I I, preferably of bronze The cap I 3 is rigidly longitudinal groove 15 that fits over a longi- "tudinal rib I6 on the shelf II] to firmly anchor this plate H to the bar 8 and to prevent move- A similar interlocking groove I! and rib I 8 are provided between the main supporting bar 8 and roller cap 13.

A roller backing bar 19, preferably of bronze, resets on the roller supporting plate II and is positioned against an upright shoulder or wall 20 of the bar 8. The front side of the roller and rupture good veneer.

backing bar I9 is of concave shape to receive and support a driven-backing roller 2|. A pressure roller 22 rests against the backing roller 2| and is held between the bottom plate and rigid roller cap l3 and has its forward surface exposed for the purpose of engaging with a log.

The upper surface of the roller supporting plate I and the lower surface of the rigid roller cap l3 are provided respectively with longitudinally extending arcuate grooves 23 and 24 which receive the backing roller 2|.

The front edge portion of the rigid roller cap l3 has a downwardly curved lip 25 that tapers substantially to a sharp edge and that engages and holds the pressure roller 22. The front edge portion of the roller supporting plate preferably has alternate teeth 26 and notches 21 and the teeth 26 are curved upwardly so as to cooperate with the lip 25 in retaining the pressure roller 22.

The roller supporting plate I and backing bar 19 are preferably made of bronze, the backing roller 2| is preferably of stainless steel and the pressure roller 22 may be either bronze or stainless steel. The cap member i3 is preferably of steel. The backing roll 2| slides freely on the backing plate i9 and has some sliding contact with the plate H and rigid roller cap l3. As friction due to sliding contact of steel and bronze is relatively low these parts will not require much .oil to efficiently lubricate the areas thereof where sliding contact takes place and the amount of oil that reaches the veneer by way of the pressure roller 22 will be negligible and will not stain or damage the veneer.

Oil for lubrication purposes is supplied through an oil conduit i that is connected with the roller cap l3.

Means are provided for positively driving the backing roller 2| and the pressure roller 22 is driven by frictional contact with the backing roller 2| and by frictional contact with th log. If the peripheral speed of the backing roller 2| is different than the peripheral speed of the log ii then the pressure roller 22 can travel at the same peripheral speed as the log and some slippage can take place between the pressure roller 22 and the backing roller 2|. For instance, in some sap wood, particularly the sap wood of fir logs, the pressure roller 22 will slip if it is not driven by any means other than the log and in so slipping is liable to tear or rupture the veneer and may render otherwise good or clear veneer unfit for use as face stock. If this pressure roll 22 is directly driven it will usually have a different peripheral speed than the log and is liable to tear When said pressure roll 22 is driven by contact both with the log 6 and the backing roll 2| enough slippage will occur between the rolls 22 and 2| to prevent. substantially all tearing and rupturing of good veneer. In operation it has been found to be practically impossible to drive a pressure roller at exactly the same peripheral speed as the log. We prefer to drive the backing roll 2| at a slightly greater peripheral speed than the log. W hen this is done then the pressure roll 22 will travel at the same peripheral speed as the log and there will be some slippage between the positively driven backing roll 22 and the pressure roll 2 To provide for endwise drifting movement of the pressure roller 22 a collar 28, Fig. 2 is preferably secured on said roller 22 near one end thereof and thrust bearings 29 ar provided on opposite sides of said collar 28. The bearings 29 are spaced apart a distance greater than the width of the collar 28 thus leaving the roller 22 free to drift endwise an amount equal to the difference between the width of the collar 28 and th spacing of the inner faces of the bearings. This drift of roller 22 helps in keeping the bar clear of dirt and particles of wood and bark and facilitates the discharge of these particles through the notches 21.

The log 6 is supported in the lathe by lathe spindles 30, one of which is shown in Fig. 3. The backing roll 2| is preferably driven by link belts 3| operating on sprocket wheels 32. The size to which the log can be turned down is limited by engagement of the sprocket wheels 32 with the lathe spindle 30. The spindle 30 is of standard size, and in lathes used with fir logs, usually is from six to eight inches in diameter. The driving sprockets such as 32, are made as small in diameter as is possible and practical but even then the sprocket wheels 32, if used directly on a pressure roll such as roll 22, will come in contact with a lathe spindle, such as spindle 30, before all of the useful veneer stock has been peeled from the log. When the sprocket wheels 32 are placed on the backing roll 2| instead of on the pressure roll 22 said sprocket wheel is farther away from the lathe spindle and this makes it possible to turn the log down to a core of smaller diameter. In practice a saving of as much as one and three quarters inches of the diameter of the log can be made.

Obviously more than one backing roller may be used in this construction if desired with the posi tive drive applied to the backing roller farthest removed from the lathe spindle.

In the operation of this pressure bar the pressure roller 22 engages a log 6 substantially over the cutting edge of a knife 33 that is peeling a thin slice of veneer 34 off of said log. The l Qrtion of the log that engages the pressure roller 22 is moving downwardly and will tend to rotate the roller 22 in the direction indicated in Fig. 1. The backing roller will tend to drive the pressure roller 22 in the same direction. slippage between the two rollers 2| and 22 may tak place at all times to allow the pressure roller 22 to travel at the same peripheral speed as the log.

All of the parts of this. pressure bar assembly are readily accessible for the purpose of inspection, cleaning and repairand all of the parts that are subject to wear are readily replaceable. Both of the rollers 2| and 22 are adequately supported throughout their full length.

The foregoing description and accompanying drawings clearly disclose preferred embodiments of this invention but it will be understood that changes in the same may be. made within the scope and spirit of the following claims.

We claim:

1. In a roller pressure bar for a veneer lathaa pressure roller adapted to engage with a log; a backing roller positioned back of said pressure roller in engagement therewith and providing a roller bearing for said pressure roller against the thrust exerted thereon by the log; driving means connected with said backing roller, said pressure roller being frictionally driven by said backing roller; housing means for said two rollers; a removable backing plate in sai'dhousing engaged by said backing roller on the side thereof opposite said pressureroller; and a removable roller supporting plate in said housing positioned below and supporting both of said rollers.

2. In a roller pressurebarfor a veneer lathe. a

pressure roller adapted to engage with a log; a backing roller positioned back of said pressure roller in engagement therewith and providing a roller bearing for said pressure roller throughout its entire length against the thrust exerted thereon by the log; driving means connected with said backing roller, said pressure roller being frictionally driven by contact with said backing roller; housing means for said two rollers; a removable bronze backing plate supporting said backing roller on the side thereof opposite said pressure roller; a removable bronze roller supporting plate positioned below and engaged by both of said rollers; and means for supplying lubricant to said housing.

3. In a roller pressure bar for a veneer lathe, a main supporting bar; a removable roller supporting plate carried by said main supporting bar; a removable backing bar carried by said main supporting bar; a backing roller positioned on said plate and resting against said backing bar; a pressure roller positioned on said roller supporting plate and engaging said backing roller, said pressure roller being adapted to engage with a log and the line of contact of said two rollers being substantially in the plane in which the thrust of a log against the pressure roller is exerted; a rigid roller cap fixedly and removably secured to said main supporting bar and extending over said backing roller and said pressure roller; and means for driving said backing roller whereby said pressure roller is frictionally driven by contact with the backing roller.

4. In a roller pressure bar for a, veneer lathe, a pressure roller adapted to engage with a log; housing means; a roller supporting plate in said housing means positioned below and supporting said roller; and spaced apart upwardly curved teeth on the forward edge portion of said roller supporting plate contacting said pressure roller, the spaces between said teeth constituting openings for the discharge of foreign matter.

5. In a roller pressure bar for a veneer lathe, a rotatively supported pressure roller adapted to engage with a log; housing means; a roller supporting plate in said housing means positioned below and supporting said roller; spaced apart upwardly curved teeth on the forward edge portion of said roller supporting plate contacting said pressure roller, the spaces between said teeth constituting openings for the discharge of foreign matter; end thrust bearing means provided in said housing; and other end thrust bearing means provided on said pressure roller, the end thrust bearing means in said housing and the end thrust bearing means on said pressure roller both being positioned longitudinally outward from the portion of the pressure roller which is adapted to contact the log and being spaced to afford lost motion between said two end thrust bearing means, whereby there is provided an endwise back and forth drift of said pressure roller during operation to facilitate discharge of foreign matter by way of the notches between said teeth.

WILLIAM J. MILLER. ALFRED C. JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 138,901 Leslie May 13, 1873 155,541 Munn Sept. 29, 1874 1,989,386 Tallquist Jan. 29, 1935 

